Solutions

SolutionsSubtopics include: (1) Describing Solutions, (2) Concentrations, (2)

Solubility & (3) the Effects of Solutes on Solutions.

SolutionsDescribing Solutions

Define: solution, solute, solvent, electrolyte, suspensions, colloidal dispersions.

Explore types of solutions.Separation of Solutions.

Concentrations Express the concentrations of

solutions in terms of: percent, parts per million, mole fraction, molarity and molality.

Solve problems involving the measurements of concentration

SolubilityDefine: miscible, saturated,

unsaturated, solubility, supersaturation. Describe Factors that effect solubility.Use “solubility rules” to predict the

solubility of an ionic compound in water.

Effects of Solutes on Solution

Effect of solutes on the boiling point and freezing point of solutions.

Solve problems involving freezing point depressions and boiling point elevation (colligative properties).

Solve problems involving solutions and chemical equations.

Effects of electrolytes on the behavior of the solution.

Describing Solutions Define: solution, solute, solvent, suspensions, colloidal dispersions, distillation filtration & chromatography.

Explore types of solutions. Identify homogenous mixtures that are not solutions.

Identify the process of separating solutions: distillation, filtration & chromatography.

Aim: What is a Chemical Solution?

Essential Questions:

1. What is a chemical solution?

2. What are some types of chemical solutions?

3. How do we separate chemical solutions? Explain.

Key Words:solution, solute,

solvent, suspensions, colloidal dispersions, distillation, Filtration,

Chromatography.

Name Some Solutions!

Q: What are some solutions you have encountered today?

Which One is a Solution?

Salt Water

Oil Water A) The Salt

Water

B) The Oil Water

C) Both

D) Neither

Deduction

Q: Based on the previous example, how can we describe a solution?

Notes

I. Describing SolutionsA. Definitions

1. Solution - homogenous mixture of a solute dissolved in a solvent.

Solutes, Solvents & Solutions

Solute

SolventSolution

Notes

2. Solute –

3. Solvent –

4. Solution –

What Makes Solutions

Homogenous?

Notes

B. “Like Dissolves Like”1. In a solution, all particles attract each

other with intermolecular forces of similar strength.i. Polar substances dissolve other polar

substances or ionic substances. ii. Nonpolar substances dissolve nonpolar

substances.

Gases

Given: Particles of different substances must attract each other with intermolecular forces of similar strength in order to form an even distribution, which is a solution.

Given: There are no intermolecular forces at work between particles in the gaseous phase

Deduction: Do gaseous particles form solutions (an even distribution)?

Strong Intermolecul

ar Forces

Weak Intermolecul

ar Forces

NoIntermolecul

ar Forces

Video Dissolving Gasses

http://www.youtube.com/watch?v=wOo5f_kvjFs

Dissolving NaClhttp://www.youtube.com/watch?v=

EBfGcTAJF4o

Notes

2. In gasses there are essentially no intermolecular forces, therefore all mixtures of gasses are solutions.

Can Solutions Exist Between Particles in Different States (Gas,

Liquid, Solid)?

Notes

C. States of Matter & Solutions1. The solute and solvent may be in different

phases as long as the particles are evenly distributed amongst each other. i. Ex: Solid NaCl dissolved in liquid water. ii. Ex: Gaseous CO2 is dissolved in liquid

soda.

Solutions Among Various Phases of

MatterExample Phase of Solute Phase of

Solvent

Metallic Alloy Solid Solid

Table salt-water Solid Liquid

Ethyl alcohol-water Liquid Liquid

CO2-water (Soda) Gas Liquid

Air Gas Gas

How Do We Determine Which Substance is a Solute & Which is the

Solvent?

Notes

D. Identification of Solutes vs. Solvents 1. If the solute and solvent are in different

phases, then solute assumes the solvent’s phase.

2. If the solute and solvent are in the same phase, then the solvent is the one that there is more of.

All solutions are homogenous mixtures,

but not all homogenous mixtures

are solutions. Can you think of an example of a homogenous mixture that is

not a solution?

SuspensionsE. Suspensions – suspensions are formed by

the physical homogenous mixture of large particles. (Solutions are made by the chemical mixture of smaller particles).1. Suspensions will settle in time (solutions will

not).2. A light beam passing through a suspension

mixture will be visible (in a solution, it will not).3. Ex. Sand + Water

Colloidal DispersionF. Colloidal Dispersion – formed when particles larger than those in solution but smaller than those in suspensions are dispersed in a medium

1. The terms dispersed substance vs dispersed medium are used for colloidal dispersion instead of solute and solvent.

2. A colloidal dispersion will not settle. 3. Tyndall effect: a light beam passing through a colloidal

dispersion will be clearly visible. 4. Ex. Whipped cream, mayonnaise, paint, gelatin &

marshmallow.

Tyndall Effect

Our Chemistry class has run out of salt and

we want to make a new batch from

collected sea water.

How do I separate the salt from the water?

G. Separating Solutions

1. Evaporation Separates dissolved SOLUTE from

SOLUTIONEx. Separating salt from water

2. Simple distillationSeparates SOLVENT from SOLUTIONEx. Obtaining pure water from sea water

3. Fractional distillation Separates one liquid from a mixture

of different liquids using differences in boiling points.Ex. Obtaining alcohol from wine or

oxygen/nitrogen from air.

4. Filtration Separates dissolved SOLUTE

from SOLUTIONEx. Filtration of blood in kidneys

5. Chromatography Separates mixtures into their

constituents by preferential adsorption by a solid.

Ex. Separating ink dyes using paper chromatography.

Cont’d

Distillationhttp://www.youtube.com/watch?v=mP4Hgui-g6U&playnext=1&list=PL73CDD6FFC04D04A4&feature=results_main

Filtration

Chromatography

Learning Check1) The solvent is the part of the solution that A. gets dissolved B. does the dissolving C. changes phase

2) Two homogenous mixtures not known as solutions are _______________________ and _______________________.

3) What is a chemical solution?

4) What are some types of chemical solutions?

5) How do we separate chemical solutions? Explain.

NotesDescribing & Separating Solutions

I.Describing SolutionsA. Definitions

1. Solution - homogenous mixture of a solute dissolved in a solvent.2. Solute – substance dissolved.3. Solvent – substance that does the dissolving.4. Solution – A homogenous mixture composed on tiny particles.

B. “Like Dissolves Like”1. In a solution, all particles attract each other with intermolecular forces of

similar strength.i. Polar molecules dissolve other polar molecules and ionic compounds. ii. Nonpolar molecules dissolve nonpolar molecules.

2. In gasses there are essentially no intermolecular forces, therefore all mixtures of gasses are solutions.

C. States of Matter & Solutions1. The solute and solvent may be in different phases as long as the particles are

evenly distributed amongst each other. i. Ex: Solid NaCl dissolved in liquid water. ii. Ex: Gaseous CO2 is dissolved in liquid soda.

D. Identification of Solutes vs. Solvents 1. If the solute and solvent are in different phases, then solute assumes the

solvent’s phase. 2. If the solute and solvent are in the same phase, then the solvent is the one

that there is more of.

E. Suspensions – suspensions are formed by the physical homogenous mixture of large particles. (Solutions are made by the chemical mixture of smaller particles).1. Suspensions will settle in time (solutions will not).2. A light bean passing through a suspension mixture will be visible

(in a solution, it will not).3. Ex. Sand + Water

F. Colloidal Dispersion – formed when particles larger than those in solution but smaller than those in suspensions are dispersed in a medium

4. The terms dispersed substance vs dispersed medium are used for colloidal dispersion instead of solute and solvent.

5. A colloidal dispersion will not settle. 6. Tyndall effect: a light beam passing through will be clearly visible. 7. Ex. Whipped cream, mayonnaise, paint, gelatin & marshmallow.

G. Seperating Solutions1. Evaporation – separates dissolved SOLUTE from

SOLUTION.i. Ex. Separating salt from water

2. Simple distillation – separates solvent from solutioni. Ex. Obtaining pure water from sea water

3. Fractional distillation – separates one liquid from a mixture of different liquids that have different boiling points.i. Ex. Obtaining ALCOHOL from wine or oxygen/nitrogen

from air.